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# Minimize the sum calculated by repeatedly removing any two elements and inserting their sum to the Array

• Difficulty Level : Easy
• Last Updated : 05 Aug, 2021

Given N elements, you can remove any two elements from the list, note their sum, and add the sum to the list. Repeat these steps while there is more than a single element in the list. The task is to minimize the sum of these chosen sums in the end.
Examples:

Input: arr[] = {1, 4, 7, 10}
Output: 39
Choose 1 and 4, Sum = 5, arr[] = {5, 7, 10}
Choose 5 and 7, Sum = 17, arr[] = {12, 10}
Choose 12 and 10, Sum = 39, arr[] = {22}
Input: arr[] = {1, 3, 7, 5, 6}
Output: 48

Approach: In order to minimize the sum, the elements that get chosen at every step must the minimum elements from the list. In order to do that efficiently, a priority queue can be used. At every step, while there is more than a single element in the list, choose the minimum and the second minimum, remove them from the list add their sum to the list after updating the running sum.
Below is the implementation of the above approach:

## C++

 `// C++ implementation of the approach``#include``using` `namespace` `std;` `// Function to return the minimized sum``int` `getMinSum(``int` `arr[], ``int` `n)``{``    ``int` `i, sum = 0;` `    ``// Priority queue to store the elements of the array``    ``// and retrieve the minimum element efficiently``    ``priority_queue<``int``, vector<``int``>, greater<``int``> > pq;` `    ``// Add all the elements``    ``// to the priority queue``    ``for` `(i = 0; i < n; i++)``        ``pq.push(arr[i]);` `    ``// While there are more than 1 elements``    ``// left in the queue``    ``while` `(pq.size() > 1)``    ``{` `        ``// Remove and get the minimum``        ``// element from the queue``        ``int` `min = pq.top();` `        ``pq.pop();` `        ``// Remove and get the second minimum``        ``// element (currently minimum)``        ``int` `secondMin = pq.top();``        ` `        ``pq.pop();` `        ``// Update the sum``        ``sum += (min + secondMin);` `        ``// Add the sum of the minimum``        ``// elements to the queue``        ``pq.push(min + secondMin);``    ``}` `    ``// Return the minimized sum``    ``return` `sum;``}` `// Driver code``int` `main()``{` `    ``int` `arr[] = { 1, 3, 7, 5, 6 };``    ``int` `n = ``sizeof``(arr)/``sizeof``(arr[0]);``    ``cout << (getMinSum(arr, n));``}` `// This code is contributed by mohit`

## Java

 `// Java implementation of the approach``import` `java.util.PriorityQueue;` `class` `GFG``{` `    ``// Function to return the minimized sum``    ``static` `int` `getMinSum(``int` `arr[], ``int` `n)``    ``{``        ``int` `i, sum = ``0``;` `        ``// Priority queue to store the elements of the array``        ``// and retrieve the minimum element efficiently``        ``PriorityQueue pq = ``new` `PriorityQueue<>();` `        ``// Add all the elements``        ``// to the prioriry queue``        ``for` `(i = ``0``; i < n; i++)``            ``pq.add(arr[i]);` `        ``// While there are more than 1 elements``        ``// left in the queue``        ``while` `(pq.size() > ``1``)``        ``{` `            ``// Remove and get the minimum``            ``// element from the queue``            ``int` `min = pq.poll();` `            ``// Remove and get the second minimum``            ``// element (currently minimum)``            ``int` `secondMin = pq.poll();` `            ``// Update the sum``            ``sum += (min + secondMin);` `            ``// Add the sum of the minimum``            ``// elements to the queue``            ``pq.add(min + secondMin);``        ``}` `        ``// Return the minimized sum``        ``return` `sum;``    ``}` `    ``// Driver code``    ``public` `static` `void` `main(String[] args)``    ``{``        ``int` `arr[] = { ``1``, ``3``, ``7``, ``5``, ``6` `};``        ``int` `n = arr.length;``        ``System.out.print(getMinSum(arr, n));``    ``}``}`

## Python3

 `# Python3 implementation of the approach` `# Function to return the minimized sum``def` `getMinSum(arr, n):` `    ``sum` `=` `0`` ` `    ``# Priority queue to store the elements of the array``    ``# and retrieve the minimum element efficiently``    ``pq ``=` `[]`` ` `    ``# Add all the elements``    ``# to the priority queue``    ``for` `i ``in` `range``( n ):``        ``pq.append(arr[i])``     ` `    ``# While there are more than 1 elements``    ``# left in the queue``    ``while` `(``len``(pq) > ``1``) :``        ` `        ``pq.sort(reverse``=``True``)``  ` `        ``# Remove and get the minimum``        ``# element from the queue``        ``min` `=` `pq[``-``1``];``       ` `        ``pq.pop();`` ` `        ``# Remove and get the second minimum``        ``# element (currently minimum)``        ``secondMin ``=` `pq[``-``1``];``         ` `        ``pq.pop();`` ` `        ``# Update the sum``        ``sum` `+``=` `(``min` `+` `secondMin);`` ` `        ``# Add the sum of the minimum``        ``# elements to the queue``        ``pq.append(``min` `+` `secondMin)``    ` `    ``# Return the minimized sum``    ``return` `sum`` ` `# Driver code``if` `__name__ ``=``=` `"__main__"``:`` ` `    ``arr ``=` `[ ``1``, ``3``, ``7``, ``5``, ``6` `]``    ``n ``=` `len``(arr)``    ``print``(getMinSum(arr, n))` `# This code is contributed by chitranayal`

## C#

 `// C# implementation of the approach``using` `System;``using` `System.Collections.Generic;``class` `GFG``{` `  ``// Function to return the minimized sum``  ``static` `int` `getMinSum(``int``[] arr, ``int` `n)``  ``{``    ``int` `i, sum = 0;` `    ``// Priority queue to store the elements of the array``    ``// and retrieve the minimum element efficiently``    ``List<``int``> pq = ``new` `List<``int``>();` `    ``// Add all the elements``    ``// to the priority queue``    ``for` `(i = 0; i < n; i++)``    ``{``      ``pq.Add(arr[i]);``    ``}` `    ``// While there are more than 1 elements``    ``// left in the queue``    ``while``(pq.Count > 1)``    ``{``      ``pq.Sort();` `      ``// Remove and get the minimum``      ``// element from the queue``      ``int` `min = pq[0];``      ``pq.RemoveAt(0);` `      ``// Remove and get the second minimum``      ``// element (currently minimum)``      ``int` `secondMin = pq[0];``      ``pq.RemoveAt(0);` `      ``// Update the sum``      ``sum += (min + secondMin);` `      ``// Add the sum of the minimum``      ``// elements to the queue``      ``pq.Add(min + secondMin);``    ``}` `    ``// Return the minimized sum``    ``return` `sum;``  ``}` `  ``// Driver code``  ``static` `public` `void` `Main ()``  ``{``    ``int``[] arr = { 1, 3, 7, 5, 6 };``    ``int` `n = arr.Length;``    ``Console.WriteLine(getMinSum(arr, n));``  ``}``}` `// This code is contributed by avanitrachhadiya2155`

## Javascript

 ``
Output:

`48`

Time Complexity : O(N * log(N))
Auxiliary Space: O(N)

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